back when i had my X force the moron at that shop set me @ 73# pull and a 309 gr arrow!!!!!!!!!! I didn't know, he said it was fine b/c it was 5 gr per in" well, My arrows were just over 24" !! Talk about feeling like dry firing!! It worked well all season however, I never had any problems. I didn't know the arrow was that light until Feb of this year. I changed arrows and then sold the damn thing anyway. I asked the question b/c Im pulling 72# and my arrows that I weighed were 360-363 gr. That's only three arrows that I weighed. If you add up the Vanes, the nock, the insert, and the tip the arrow should weigh only 358.25 gr. So I wondered if I had anythat were too light b/c IBO says at 72# it needs to be at least 360 gr. I know that my arrows are short 24 1/4 to be exact. So they are stiff and I only have a 26.5 " draw, but I wanted everything to be alright. I got some good advice from some guys on here so hopefully everything will good.